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Full text of "Handbook Of Chemical Engineering - I"

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194
CHEMICAL ENGINEERING
two types of machines that are largely, almost exclusively, used. These are the jaw type and the gyratory type. Of the jaw type of machine, there are two modifications, one the Blake type and the other the Dodge. In general, Jaw Breakers consist of a heavy iron or steel frame embodying one fixed jaw and one movable jaw. The movable jaw is suspended from the shaft or hinge forming the
FIG. 1.—Blake crusher.
upper end of the jaw, the reciprocating movement being applied at or near its lower end. The movement is applied by means of a cam on the driven shaft of the machine, which raises and lowers a pitman, which imparts motion through
FIG. 2.—Dodge crusher.
a pair of toggles. As the cam raises the pitman, the toggles assume an angular position, the swinging jaw being held against the front toggle by means of a rod and coil spring, as shown in the accompanying illustration. During the succeeding semi-revolution of the shaft, the cam lowers the pitman, straightening out the toggles, thus forcing forward the lower end of the swinging jaw. The rock between the two jaws of the machine is thereby compressed and ruptured. The wear is taken upon removable jaw plates, which are fitted to both the stationary and moving jaw. The features of this machine include a rectangular opening which will take a large rock in comparison to the total weight of the machine; When the swinging jaw recedes from the stationary one, the discharge opening is increased in size, with the result that the discharge varies in size between wide limits. The product of machines of this type may consist of slabs of rock nearly